This invention relates to an apparatus for chiropractic therapy and massage, and more particularly an apparatus which performs a chiropractic therapy and massage, using pressure rollers which make a reciprocating movement.
The apparatus of this sort generally has a construction which comprises a housing with a sheet stretched over an open side thereof and a support frame supporting pressure means carrying a plurality of pressure rollers and mounted for reciprocating movement in the housing. The support frame is driven by a power source such as a reversible motor for recprocating movement within the housing, whereby a user lying on the sheet is massaged by the pressure rollers of the pressure means.
Strictly speaking, chiropractic therapy and massage are different in a sense. The former refers to pressure treatment on the body by pressure rollers temporarily held in a fixed position, while the latter refers to the operation of massage of the body by pressure rollers moved with the movement of the support frame. However, both chiropractic therapy and massage are usually thought to be the same thing, so their strict distinction is not always made in the following description.
With the chiropractic therapy and massage apparatus of the above construction, the user's weight is applied to the support frame. This, therefore, tends to obstruct the smooth reciprocating movement of the support frame and thus reduce the chiropractic or massage effect. It is thus necessary to provide a mechanism for ensuring the reliable transmission of the driving force from the power source to the support frame.
In the well-known chiropractic therapy and massage apparatus, the driving force from the power source is transmitted to the support frame by a chain or a wire. Where a chain is used, the driving force from the power source can be securely transmitted to the supported frame because the chain does not slip. On the demerit side, however, the chain is very expensive compared with the wire, and also the use of the chain leads to the generation of noise. In the case of using a wire, although it is inexpensive compared with the chain and does not produce noise, the wire is liable to generate slip because it is subject to elongation with a change of its tension caused when driving the support frame with a heavy load. The generation of slip is undesired from the standpoint of smooth driving of the support frame.
In another aspect, in the well-known chiropractic therapy and massage apparatus the stroke of reciprocation of the support frame along the housing is usually fixed and cannot be freely varied by the user. More particularly, with the prior-art chiropractic therapy and massage apparatus the stroke of the support frame, i.e., the stroke of the pressure mans including a plurality of pressure rollers, is set such that the pressure rollers are moved substantially over the whole body of the user lying on sheet. Therefore, while the apparatus is useful when it is desired to obtain chiropractic therapy or massage over the whole body, inconvenience is felt when it is desired to obtain concentrated chiropractic therapy or massage on a portion of the body.
In a further aspect, satisfactory chiropractic therapy or massage effect cannot be obtained with the prior apparatus unless strong urging forces are exerted by the pressure rollers of the pressure means running within the housing to the body of the user lying on the sheet. Accordingly, cloth having an expansible characteristic is used as the sheet stretched on the open said of the housing so that it is deformed by the user lying on it to let the user's body be sufficiently sunk in the housing and thereby increase the urging force applied by the pressure rollers to the user.
However, if the urging force exerted by the pressure rollers is increased in this way, it is likely that the large load is applied to the sheet when the user lies thereon or the body of the user is vertically rocked with the sheet as the pressure rollers are moved along the underside of the user. Therefore, the user's body is liable to strike through the sheet the hard inner wall of the housing or wire or chain stretched within the housing and driven by the power source for driving the pressure rollers. If this occurs, the user feels displeasure. Also, the sheet is rubbed by the wire or the chain so that it is damaged soon.
In a still further aspect, it has recently been contemplated to enhance the chiropractic therapy or massage effect of pressure rollers by permitting strong pressure to be applied to what is called particular physiological spots of the body with a number of protuberances provided on the outer periphery of the pressure rollers. The particular physiological spots of the body are located along the opposite sides of the backbone, so that it is in general practice to provide a pair of pressure rollers on a shaft such that these rollers are moved along the opposite sides of the backbone.
However, the backbone becomes progressively thicker, although slightly, from the spinal column toward the lumber vertebra, and the distance between the opposite side particular physiological spots is progressively increased with the increase of the thickness of the backbone. Therefore, where a pair of pressure rollers provided with peripheral protuberances are driven with shaft carrying them at a fixed spacing through the housing, the pressure effect of the protuberances are not given to all of the particular physiological spots, that is, satisfactory chiropractic therapy and massage cannot be obtained.
Even in this case, the protuberances provided on the periphery of the pair of pressure rollers press the particular physiological spots and can give local pressure effect. However, it is only small local portions of the body that are given strong forces by the protuberances of the pressure rollers, and what is called massage effect, i.e., the effect of rubbing the whole muscle of the body, is hardly obtained. Therefore, for concurrently obtaining both the chiropractic therapy effect and massage effect it is necessary to provide pressure means having pressure rollers without any protuberance and serving to provide the massage effect as well as pressure means having pressure rollers provided with protuberances.
In a yet further aspect, the smaller the stroke of the support frame the greater the number of cycles of pressure application by the pressure rollers per unit time so that the greater is the massage effect. In the usual chiropractic therapy and massage apparatus the pressure means has only a single pair of pressure rollers for massaging the whole body from the neck through the hip to the legs, to improve the chiropractic effect or massage effect. There has been proposed an apparatus which has two pressure roller pairs mounted in a support frame in such a manner that these pairs are spaced apart from each other in the longitudinal direction of the housing. With this type of chiropractic therapy and massage apparatus, the pressure roller pair on the side of the head of the user serves to apply pressure to a portion of the body from the neck to the hip while the other pressure roller pair applies pressure to the other portion of the body, namely from the hip to the end of the legs. In this chiropractic therapy and massage apparatus, the pressure rollers of each pair are mounted on a shaft with the same space provided for the protuberance of one roller of the pair with respect to that of the other roller. However, the particular physiological spots on the opposite side of the backbone and those of the legs are spaced apart by different distances. In the naturally lying state of the body, the distance between the particular pysiological spots of the legs is greater than the distance between the those on the opposite sides of the backbone. Therefore, with the fixed space of the protuberances of the pressure rollers in the axial direction of the shaft thereof, the user lying in the natural state cannot obtain pressure effects concurrently on the particular pysiological spots on the opposite sides of the backbone and on those of the legs. If it is intended to obtain both the chiropractic therapy effect and massage effect of the pressure roller pairs, the user has to change his posture from the natural one, for instance by changing the distance between the legs to meet the lateral spacing of the protuberances of the pressure roller pair positioned on the side of the legs.
It is a primary object of this invention to provide an apparatus for chiropractic therapy and massage, in which the support frame is smoothly reciprocated by using a wire.